Charles Ellicott Commentary Isaiah 30:17

"One thousand [shall flee] at the threat of one; at the threat of five shall ye flee: till ye be left as a beacon upon the top of a mountain, and as an ensign on a hill." — Isaiah 30:17 (ASV)

One thousand shall flee at the rebuke of one. —The hyperbole is natural and common enough (Deuteronomy 32:30; Joshua 23:10; Leviticus 26:8); but the fact that the inscription of King Piankhi Mer-Amon, translated in Records of the Past, Volume II, page 84, gives it in the very same words (“many shall turn their backs on a few; and one shall rout a thousand”) as his boast of the strength of Egypt, may have given a special touch of sarcasm to Isaiah’s words.

As a beacon upon the top of a mountain. —Literally, as a pine. With a poet’s eye, the prophet paints two of the most striking emblems of solitude: the tall pine standing by itself on the mountain height, the flagstaff seen alone far off against the sky. (Compare the lowlier imagery of Isaiah 1:8.)